Eye examining instrument

Abstract

The instrument projects, to the anterior portion of a human eye, plural component beams images of which form a single mark image when said component beams are aligned, and inspects if said component images of the mark are aligned. The instrument is exactly positioned with respect to the human eye when said component images are aligned. The mark image is observed through a finder of the instrument or by an infrared-visible image converter connected to the instrument, or it is refocused on and detected by photoelectric cells.

What I claim 
     
       1. An image examining instrument comprising: an eye inspecting system;   a mark;   a prism for splitting an image of the mark into plural mark images;   a beam projection system for projecting beams for forming an image of the mark at an anterior portion of the eye;   imaging optical means, directed at the anterior portion of the eye for imaging the beams reflected by said anterior portion; and   a mark detecting system for detecting the positions of a plane which is in conjugate relationship with said anterior portion of the eye with respect to said imaging optical means, said mark and said prism being so arranged that when positioning of the eye and instrument is correct, the mark images are aligned.   
     
     
       2. An eye examining instrument according to claim 1 wherein said mark detecting system comprises an image display system and an image transmitting system for transmitting the image of said marks to said image display system. 
     
     
       3. An eye examining instrument according to claim 2 wherein said image transmitting system comprises a bundle of fibers and lens means. 
     
     
       4. An eye examining instrument according to claim 2 wherein said image transmitting system comprises plural lens groups. 
     
     
       5. An eye examining instrument according to claim 2 wherein said image display system comprises a pick-up tube and a cathode ray tube. 
     
     
       6. An eye examining instrument according to claim 1 wherein said mark detecting system comprises a photoelectric device and display means operated by the output of said photoelectric device. 
     
     
       7. An eye examining instrument according to claim 6 wherein said photoelectric device comprises a photoelectric cell and masking means provided in front thereof. 
     
     
       8. An eye examining instrument according to claim 1 wherein said eye inspecting system comprises objective lens means provided in facing relationship with the eye to be examined. 
     
     
       9. An eye examining instrument according to claim 8 wherein said eye inspecting system comprises an image forming lens group, an observing system and an illuminating system provided on the image side of said objective lens means. 
     
     
       10. An eye examining instrument according to claim 9 wherein said observing system comprises at least a lens group, a pick-up device and a display device. 
     
     
       11. An eye examining instrument according to claim 9 wherein said eye inspecting system is provided with a photographic film behind said image forming lens group. 
     
     
       12. An eye examining instrument according to claim 1 wherein said eye inspecting system, said beam projection system and said imaging optical means are provided in common with objective lens means arranged in facing relationship with the eye to be examined. 
     
     
       13. An eye examining instrument according to claim 1 wherein an optical axis of said beam projection system intersects an optical axis of said eye inspecting system. 
     
     
       14. An eye examining instrument comprising: an eye inspecting system adapted to be focused on a fundus of an eye to be inspected;   observation means for observing an image surface of said eye inspecting system;   a mark projection system for projecting plural beams each forming an image of a mark and mutually joining at the anterior portion of the eye and arranged at a predetermined position;   receiving optical means, adapted to oppose the eye, for receiving the images of the marks reflected by the anterior portion of the eye; and   image transmitting means, optically coupled with said receiving optical means, for transmitting images of marks to said observation means, wherein when positioning of said eye and said instrument is correct, the images of the marks are aligned in said observation means.   
     
     
       15. An instrument according to claim 14, wherein said mark projection system projects the beams through said receiving optical means. 
     
     
       16. An instrument according to claim 14, wherein said eye inspecting system comprises an objective lens adapted to oppose the eye to be inspected, an image forming lens arranged co-axially with said objective lens, an aperture stop disposed between said objective lens and said image forming lens and illuminating means for illuminating said eye fundus, wherein said mark projection system projects the beams through said objective lens. 
     
     
       17. An instrument according to claim 14, wherein said eye inspecting system comprises an objective lens adapted to oppose the eye to be inspected, an image forming lens arranged co-axially with said objective lens, an aperture stop disposed between said objective lens and said image forming lens, photosensitive means for receiving an image of the fundus of the eye formed by said image forming lens, and illuminating means for illuminating said eye fundus, and wherein said objective lens functions also as said imaging lens. 
     
     
       18. An instrument according to claim 14, wherein said image transmitting means includes a bundle of optical fibers. 
     
     
       19. An instrument according to claim 14, wherein the image of the eye fundus and the images of the marks appear side by side in said observation means. 
     
     
       20. An instrument according to claim 14, wherein the image of the eye fundus and the images of the marks occur in superposed relationship.